Common(3) User Contributed Perl Documentation Common(3)NAME
Test::Cmd::Common - module for common Test::Cmd error handling
SYNOPSIS
use Test::Cmd::Common;
$test = Test::Cmd::Common->new(string => 'functionality being tested',
prog => 'program_under_test',
);
$test->run(chdir => 'subdir', fail => '$? != 0',
flags => '-x', targets => '.',
stdout => <<_EOF_, stderr => <<_EOF_);
expected standard output
_EOF_
expected error output
_EOF_
$test->subdir('subdir', ...);
$test->read(\$contents, 'file');
$test->read(\@lines, 'file');
$test->write('file', <<_EOF_);
contents of the file
_EOF_
$test->file_matches();
$test->must_exist('file', ['subdir', 'file'], ...);
$test->must_not_exist('file', ['subdir', 'file'], ...);
$test->copy('src_file', 'dst_file');
$test->chmod($mode, 'file', ...);
$test->sleep;
$test->sleep($seconds);
$test->touch('file', ...);
$test->unlink('file', ...);
DESCRIPTION
The "Test::Cmd::Common" module provides a simple, high-level interface
for writing tests of executable commands and scripts, especially
commands and scripts that interact with the file system. All methods
throw exceptions and exit on failure. This makes it unnecessary to add
explicit checks for return values, making the test scripts themselves
simpler to write and easier to read.
The "Test::Cmd::Common" class is a subclass of "Test::Cmd". In
essence, "Test::Cmd::Common" is a wrapper that treats common
"Test::Cmd" error conditions as exceptions that terminate the test.
You can use "Test::Cmd::Common" directly, or subclass it for your
program and add additional (or override) methods to tailor it to your
program's specific needs. Alternatively, "Test::Cmd::Common" serves as
a useful example of how to define your own "Test::Cmd" subclass.
The "Test::Cmd::Common" module provides the following importable
variables:
$_exe
The executable file suffix. This value is normally available as
$Config{_exe} in Perl version 5.005 and later. The
"Test::Cmd::Common" module figures it out via other means in
earlier versions.
$_o The object file suffix. This value is normally available from
$Config{_o} in Perl version 5.005 and later. The
"Test::Cmd::Common" module figures it out via other means in
earlier versions.
$_a The library file suffix. This value is normally available from as
$Config{_a} in Perl version 5.005 and later. The
"Test::Cmd::Common" module figures it out via other means in
earlier versions.
$_so
The shared library file suffix. This value is normally available
as $Config{_so} in Perl version 5.005 and later. The
"Test::Cmd::Common" module figures it out via other means in
earlier versions.
$_is_win32
A Boolean value that reflects whether the current platform is a
Win32 system.
METHODS
"new"
Creates a new test environment object. Any arguments are keyword-
value pairs that are passed through to the construct method for the
base class from which we inherit our methods (that is, the
"Test::Cmd" class). In the normal case, this should be the program
to be tested and a description of the functionality being tested:
$test = Test::Cmd::Common->new(prog => 'my_program',
string => 'cool new feature');
By default, methods that match actual versus expected output (the
"run", and "file_matches" methods) use an exact match. Tests that
require regular expression matches can specify this on
initialization of the test environment:
$test = Test::Cmd::Common->new(prog => 'my_program',
string => 'cool new feature',
match_sub => \&Test::Cmd::diff_regex);
or by executing the following after initialization of the test
environment:
$test->match_sub(\&Test::Cmd::diff_regex);
Creates a temporary working directory for the test environment and
changes directory to it.
Exits NO RESULT if the object can not be created, the temporary
working directory can not be created, or the current directory
cannot be changed to the temporary working directory.
"run"
Runs the program under test, checking that the test succeeded.
Arguments are keyword-value pairs that affect the manner in which
the program is executed or the results are evaluated.
chdir => 'subdir'
fail => 'failure condition' # default is '$? != 0'
flags => 'Cons flags'
stderr => 'expected error output'
stdout => 'expected standard output'
targets => 'targets to build'
The test fails if:
-- The specified failure condition is met. The default failure
condition is '$? != 0', i.e. the program exits unsuccesfully.
A not-uncommon alternative is:
$test->run(fail => '$? == 0'); # expect failure
when testing how the program handles errors.
-- Actual standard output does not match expected standard output
(if any). The expected standard output is an array of lines
or a scalar which will be split on newlines.
-- Actual error output does not match expected error output (if
any). The expected error output is an array of lines or a
scalar which will be split on newlines.
This method will test for NO error output by default if no
expected error output is specified (unlike standard output).
The error output test may be explicitly suppressed by
specifying undef as the "expected" error output:
$test->run(stderr => undef);
By default, this method performs an exact match of actual vs.
expected standard output or error output:
$test->run(stdout => <<_EOF_, stderr => _EOF_);
An expected STDOUT line, which must be matched exactly.
_EOF_
One or more expected STDERR lines,
which must be matched exactly.
_EOF_
Tests that require regular expression matches should be executed
using a test environment that calls the "match_sub" method as
follows:
$test->match_sub(\&Test::Cmd::diff_regex);
$test->run(stdout => <<_EOF_, stderr => _EOF_);
An expected (STDOUT|standard output) line\.
_EOF_
One or more expected (STDERR|error output) lines,
which may contain (regexes|regular expressions)\.
_EOF_
"subdir"
Creates one or more subdirectories in the temporary working
directory. Exits NO RESULT if the number of subdirectories
actually created does not match the number expected. For
compatibility with its superclass method, returns the number of
subdirectories actually created.
"read"
Reads the contents of a file, depositing the contents in the
destination referred to by the first argument (a scalar or array
reference). If the file name is not an absolute path name, it is
relative to the temporary working directory. Exits NO RESULT if
the file could not be read for any reason. For compatibility with
its superclass method, returns TRUE on success.
"write"
Writes a file with the specified contents. If the file name is not
an absolute path name, it is relative to the temporary working
directory. Exits NO RESULT if there were any errors writing the
file. For compatibility with its superclass method, returns TRUE
on success.
$test->write('file', <<_EOF_);
contents of the file
_EOF_
"file_matches"
Matches the contents of the specified file (first argument) against
the expected contents. The expected contents are an array of lines
or a scalar which will be split on newlines. By default, each
expected line must match exactly its corresponding line in the
file:
$test->file_matches('file', <<_EOF_);
Line #1.
Line #2.
_EOF_
Tests that require regular expression matches should be executed
using a test environment that calls the "match_sub" method as
follows:
$test->match_sub(\&Test::Cmd::diff_regex);
$test->file_matches('file', <<_EOF_);
The (1st|first) line\.
The (2nd|second) line\.
_EOF_
"must_exist"
Ensures that the specified files must exist. Files may be
specified as an array reference of directory components, in which
case the pathname will be constructed by concatenating them. Exits
FAILED if any of the files does not exist.
"must_not_exist"
Ensures that the specified files must not exist. Files may be
specified as an array reference of directory components, in which
case the pathname will be constructed by concatenating them. Exits
FAILED if any of the files exists.
"copy"
Copies a file from the source (first argument) to the destination
(second argument). Exits NO RESULT if the file could not be copied
for any reason.
"chmod"
Changes the permissions of a list of files to the specified mode
(first argument). Exits NO RESULT if any file could not be changed
for any reason.
"sleep"
Sleeps at least the specified number of seconds. If no number is
specified, sleeps at least a minimum number of seconds necessary to
advance file time stamps on the current system. Sleeping more
seconds is all right. Exits NO RESULT if the time slept was less
than specified.
"touch"
Updates the access and modification times of the specified files.
Exits NO RESULT if any file could not be modified for any reason.
"unlink"
Removes the specified files. Exits NO RESULT if any file could not
be removed for any reason.
ENVIRONMENT
The "Test::Cmd::Common" module also uses the "PRESERVE",
"PRESERVE_FAIL", "PRESERVE_NO_RESULT", and "PRESERVE_PASS" environment
variables from the "Test::Cmd" module. See the "Test::Cmd"
documentation for details.
SEE ALSOperl(1), Test::Cmd(3).
The most involved example of using the "Test::Cmd::Common" module to
test a real-world application is the "cons-test" testing suite for the
Cons software construction utility. The suite sub-classes
"Test::Cmd::Common" to provide common, application-specific
infrastructure across a large number of end-to-end application tests.
The suite, and other information about Cons, is available at:
http://www.dsmit.com/cons
AUTHOR
Steven Knight, knight@baldmt.com
ACKNOWLEDGEMENTS
Thanks to Johan Holmberg for asking the question that led to the
creation of this package.
The general idea of testing commands in this way, as well as the test
reporting of the "pass", "fail" and "no_result" methods, come from the
testing framework invented by Peter Miller for his Aegis project change
supervisor. Aegis is an excellent bit of work which integrates
creation and execution of regression tests into the software
development process. Information about Aegis is available at:
http://www.tip.net.au/~millerp/aegis.html
perl v5.14.0 2001-09-05 Common(3)
